xref: /linux/net/sunrpc/xprtrdma/transport.c (revision 249ebf3f65f8530beb2cbfb91bff1d83ba88d23c)
1 // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
2 /*
3  * Copyright (c) 2014-2017 Oracle.  All rights reserved.
4  * Copyright (c) 2003-2007 Network Appliance, Inc. All rights reserved.
5  *
6  * This software is available to you under a choice of one of two
7  * licenses.  You may choose to be licensed under the terms of the GNU
8  * General Public License (GPL) Version 2, available from the file
9  * COPYING in the main directory of this source tree, or the BSD-type
10  * license below:
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  *
16  *      Redistributions of source code must retain the above copyright
17  *      notice, this list of conditions and the following disclaimer.
18  *
19  *      Redistributions in binary form must reproduce the above
20  *      copyright notice, this list of conditions and the following
21  *      disclaimer in the documentation and/or other materials provided
22  *      with the distribution.
23  *
24  *      Neither the name of the Network Appliance, Inc. nor the names of
25  *      its contributors may be used to endorse or promote products
26  *      derived from this software without specific prior written
27  *      permission.
28  *
29  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
30  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
31  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
32  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
33  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
34  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
35  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
36  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
37  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
38  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
39  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
40  */
41 
42 /*
43  * transport.c
44  *
45  * This file contains the top-level implementation of an RPC RDMA
46  * transport.
47  *
48  * Naming convention: functions beginning with xprt_ are part of the
49  * transport switch. All others are RPC RDMA internal.
50  */
51 
52 #include <linux/module.h>
53 #include <linux/slab.h>
54 #include <linux/seq_file.h>
55 #include <linux/smp.h>
56 
57 #include <linux/sunrpc/addr.h>
58 #include <linux/sunrpc/svc_rdma.h>
59 
60 #include "xprt_rdma.h"
61 #include <trace/events/rpcrdma.h>
62 
63 /*
64  * tunables
65  */
66 
67 static unsigned int xprt_rdma_slot_table_entries = RPCRDMA_DEF_SLOT_TABLE;
68 unsigned int xprt_rdma_max_inline_read = RPCRDMA_DEF_INLINE;
69 unsigned int xprt_rdma_max_inline_write = RPCRDMA_DEF_INLINE;
70 unsigned int xprt_rdma_memreg_strategy		= RPCRDMA_FRWR;
71 int xprt_rdma_pad_optimize;
72 static struct xprt_class xprt_rdma;
73 
74 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
75 
76 static unsigned int min_slot_table_size = RPCRDMA_MIN_SLOT_TABLE;
77 static unsigned int max_slot_table_size = RPCRDMA_MAX_SLOT_TABLE;
78 static unsigned int min_inline_size = RPCRDMA_MIN_INLINE;
79 static unsigned int max_inline_size = RPCRDMA_MAX_INLINE;
80 static unsigned int max_padding = PAGE_SIZE;
81 static unsigned int min_memreg = RPCRDMA_BOUNCEBUFFERS;
82 static unsigned int max_memreg = RPCRDMA_LAST - 1;
83 static unsigned int dummy;
84 
85 static struct ctl_table_header *sunrpc_table_header;
86 
87 static struct ctl_table xr_tunables_table[] = {
88 	{
89 		.procname	= "rdma_slot_table_entries",
90 		.data		= &xprt_rdma_slot_table_entries,
91 		.maxlen		= sizeof(unsigned int),
92 		.mode		= 0644,
93 		.proc_handler	= proc_dointvec_minmax,
94 		.extra1		= &min_slot_table_size,
95 		.extra2		= &max_slot_table_size
96 	},
97 	{
98 		.procname	= "rdma_max_inline_read",
99 		.data		= &xprt_rdma_max_inline_read,
100 		.maxlen		= sizeof(unsigned int),
101 		.mode		= 0644,
102 		.proc_handler	= proc_dointvec_minmax,
103 		.extra1		= &min_inline_size,
104 		.extra2		= &max_inline_size,
105 	},
106 	{
107 		.procname	= "rdma_max_inline_write",
108 		.data		= &xprt_rdma_max_inline_write,
109 		.maxlen		= sizeof(unsigned int),
110 		.mode		= 0644,
111 		.proc_handler	= proc_dointvec_minmax,
112 		.extra1		= &min_inline_size,
113 		.extra2		= &max_inline_size,
114 	},
115 	{
116 		.procname	= "rdma_inline_write_padding",
117 		.data		= &dummy,
118 		.maxlen		= sizeof(unsigned int),
119 		.mode		= 0644,
120 		.proc_handler	= proc_dointvec_minmax,
121 		.extra1		= SYSCTL_ZERO,
122 		.extra2		= &max_padding,
123 	},
124 	{
125 		.procname	= "rdma_memreg_strategy",
126 		.data		= &xprt_rdma_memreg_strategy,
127 		.maxlen		= sizeof(unsigned int),
128 		.mode		= 0644,
129 		.proc_handler	= proc_dointvec_minmax,
130 		.extra1		= &min_memreg,
131 		.extra2		= &max_memreg,
132 	},
133 	{
134 		.procname	= "rdma_pad_optimize",
135 		.data		= &xprt_rdma_pad_optimize,
136 		.maxlen		= sizeof(unsigned int),
137 		.mode		= 0644,
138 		.proc_handler	= proc_dointvec,
139 	},
140 };
141 
142 #endif
143 
144 static const struct rpc_xprt_ops xprt_rdma_procs;
145 
146 static void
147 xprt_rdma_format_addresses4(struct rpc_xprt *xprt, struct sockaddr *sap)
148 {
149 	struct sockaddr_in *sin = (struct sockaddr_in *)sap;
150 	char buf[20];
151 
152 	snprintf(buf, sizeof(buf), "%08x", ntohl(sin->sin_addr.s_addr));
153 	xprt->address_strings[RPC_DISPLAY_HEX_ADDR] = kstrdup(buf, GFP_KERNEL);
154 
155 	xprt->address_strings[RPC_DISPLAY_NETID] = RPCBIND_NETID_RDMA;
156 }
157 
158 static void
159 xprt_rdma_format_addresses6(struct rpc_xprt *xprt, struct sockaddr *sap)
160 {
161 	struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
162 	char buf[40];
163 
164 	snprintf(buf, sizeof(buf), "%pi6", &sin6->sin6_addr);
165 	xprt->address_strings[RPC_DISPLAY_HEX_ADDR] = kstrdup(buf, GFP_KERNEL);
166 
167 	xprt->address_strings[RPC_DISPLAY_NETID] = RPCBIND_NETID_RDMA6;
168 }
169 
170 void
171 xprt_rdma_format_addresses(struct rpc_xprt *xprt, struct sockaddr *sap)
172 {
173 	char buf[128];
174 
175 	switch (sap->sa_family) {
176 	case AF_INET:
177 		xprt_rdma_format_addresses4(xprt, sap);
178 		break;
179 	case AF_INET6:
180 		xprt_rdma_format_addresses6(xprt, sap);
181 		break;
182 	default:
183 		pr_err("rpcrdma: Unrecognized address family\n");
184 		return;
185 	}
186 
187 	(void)rpc_ntop(sap, buf, sizeof(buf));
188 	xprt->address_strings[RPC_DISPLAY_ADDR] = kstrdup(buf, GFP_KERNEL);
189 
190 	snprintf(buf, sizeof(buf), "%u", rpc_get_port(sap));
191 	xprt->address_strings[RPC_DISPLAY_PORT] = kstrdup(buf, GFP_KERNEL);
192 
193 	snprintf(buf, sizeof(buf), "%4hx", rpc_get_port(sap));
194 	xprt->address_strings[RPC_DISPLAY_HEX_PORT] = kstrdup(buf, GFP_KERNEL);
195 
196 	xprt->address_strings[RPC_DISPLAY_PROTO] = "rdma";
197 }
198 
199 void
200 xprt_rdma_free_addresses(struct rpc_xprt *xprt)
201 {
202 	unsigned int i;
203 
204 	for (i = 0; i < RPC_DISPLAY_MAX; i++)
205 		switch (i) {
206 		case RPC_DISPLAY_PROTO:
207 		case RPC_DISPLAY_NETID:
208 			continue;
209 		default:
210 			kfree(xprt->address_strings[i]);
211 		}
212 }
213 
214 /**
215  * xprt_rdma_connect_worker - establish connection in the background
216  * @work: worker thread context
217  *
218  * Requester holds the xprt's send lock to prevent activity on this
219  * transport while a fresh connection is being established. RPC tasks
220  * sleep on the xprt's pending queue waiting for connect to complete.
221  */
222 static void
223 xprt_rdma_connect_worker(struct work_struct *work)
224 {
225 	struct rpcrdma_xprt *r_xprt = container_of(work, struct rpcrdma_xprt,
226 						   rx_connect_worker.work);
227 	struct rpc_xprt *xprt = &r_xprt->rx_xprt;
228 	unsigned int pflags = current->flags;
229 	int rc;
230 
231 	if (atomic_read(&xprt->swapper))
232 		current->flags |= PF_MEMALLOC;
233 	rc = rpcrdma_xprt_connect(r_xprt);
234 	xprt_clear_connecting(xprt);
235 	if (!rc) {
236 		xprt->connect_cookie++;
237 		xprt->stat.connect_count++;
238 		xprt->stat.connect_time += (long)jiffies -
239 					   xprt->stat.connect_start;
240 		xprt_set_connected(xprt);
241 		rc = -EAGAIN;
242 	} else
243 		rpcrdma_xprt_disconnect(r_xprt);
244 	xprt_unlock_connect(xprt, r_xprt);
245 	xprt_wake_pending_tasks(xprt, rc);
246 	current_restore_flags(pflags, PF_MEMALLOC);
247 }
248 
249 /**
250  * xprt_rdma_inject_disconnect - inject a connection fault
251  * @xprt: transport context
252  *
253  * If @xprt is connected, disconnect it to simulate spurious
254  * connection loss. Caller must hold @xprt's send lock to
255  * ensure that data structures and hardware resources are
256  * stable during the rdma_disconnect() call.
257  */
258 static void
259 xprt_rdma_inject_disconnect(struct rpc_xprt *xprt)
260 {
261 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
262 
263 	trace_xprtrdma_op_inject_dsc(r_xprt);
264 	rdma_disconnect(r_xprt->rx_ep->re_id);
265 }
266 
267 /**
268  * xprt_rdma_destroy - Full tear down of transport
269  * @xprt: doomed transport context
270  *
271  * Caller guarantees there will be no more calls to us with
272  * this @xprt.
273  */
274 static void
275 xprt_rdma_destroy(struct rpc_xprt *xprt)
276 {
277 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
278 
279 	cancel_delayed_work_sync(&r_xprt->rx_connect_worker);
280 
281 	rpcrdma_xprt_disconnect(r_xprt);
282 	rpcrdma_buffer_destroy(&r_xprt->rx_buf);
283 
284 	xprt_rdma_free_addresses(xprt);
285 	xprt_free(xprt);
286 
287 	module_put(THIS_MODULE);
288 }
289 
290 /* 60 second timeout, no retries */
291 static const struct rpc_timeout xprt_rdma_default_timeout = {
292 	.to_initval = 60 * HZ,
293 	.to_maxval = 60 * HZ,
294 };
295 
296 /**
297  * xprt_setup_rdma - Set up transport to use RDMA
298  *
299  * @args: rpc transport arguments
300  */
301 static struct rpc_xprt *
302 xprt_setup_rdma(struct xprt_create *args)
303 {
304 	struct rpc_xprt *xprt;
305 	struct rpcrdma_xprt *new_xprt;
306 	struct sockaddr *sap;
307 	int rc;
308 
309 	if (args->addrlen > sizeof(xprt->addr))
310 		return ERR_PTR(-EBADF);
311 
312 	if (!try_module_get(THIS_MODULE))
313 		return ERR_PTR(-EIO);
314 
315 	xprt = xprt_alloc(args->net, sizeof(struct rpcrdma_xprt), 0,
316 			  xprt_rdma_slot_table_entries);
317 	if (!xprt) {
318 		module_put(THIS_MODULE);
319 		return ERR_PTR(-ENOMEM);
320 	}
321 
322 	xprt->timeout = &xprt_rdma_default_timeout;
323 	xprt->connect_timeout = xprt->timeout->to_initval;
324 	xprt->max_reconnect_timeout = xprt->timeout->to_maxval;
325 	xprt->bind_timeout = RPCRDMA_BIND_TO;
326 	xprt->reestablish_timeout = RPCRDMA_INIT_REEST_TO;
327 	xprt->idle_timeout = RPCRDMA_IDLE_DISC_TO;
328 
329 	xprt->resvport = 0;		/* privileged port not needed */
330 	xprt->ops = &xprt_rdma_procs;
331 
332 	/*
333 	 * Set up RDMA-specific connect data.
334 	 */
335 	sap = args->dstaddr;
336 
337 	/* Ensure xprt->addr holds valid server TCP (not RDMA)
338 	 * address, for any side protocols which peek at it */
339 	xprt->prot = IPPROTO_TCP;
340 	xprt->xprt_class = &xprt_rdma;
341 	xprt->addrlen = args->addrlen;
342 	memcpy(&xprt->addr, sap, xprt->addrlen);
343 
344 	if (rpc_get_port(sap))
345 		xprt_set_bound(xprt);
346 	xprt_rdma_format_addresses(xprt, sap);
347 
348 	new_xprt = rpcx_to_rdmax(xprt);
349 	rc = rpcrdma_buffer_create(new_xprt);
350 	if (rc) {
351 		xprt_rdma_free_addresses(xprt);
352 		xprt_free(xprt);
353 		module_put(THIS_MODULE);
354 		return ERR_PTR(rc);
355 	}
356 
357 	INIT_DELAYED_WORK(&new_xprt->rx_connect_worker,
358 			  xprt_rdma_connect_worker);
359 
360 	xprt->max_payload = RPCRDMA_MAX_DATA_SEGS << PAGE_SHIFT;
361 
362 	return xprt;
363 }
364 
365 /**
366  * xprt_rdma_close - close a transport connection
367  * @xprt: transport context
368  *
369  * Called during autoclose or device removal.
370  *
371  * Caller holds @xprt's send lock to prevent activity on this
372  * transport while the connection is torn down.
373  */
374 void xprt_rdma_close(struct rpc_xprt *xprt)
375 {
376 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
377 
378 	rpcrdma_xprt_disconnect(r_xprt);
379 
380 	xprt->reestablish_timeout = 0;
381 	++xprt->connect_cookie;
382 	xprt_disconnect_done(xprt);
383 }
384 
385 /**
386  * xprt_rdma_set_port - update server port with rpcbind result
387  * @xprt: controlling RPC transport
388  * @port: new port value
389  *
390  * Transport connect status is unchanged.
391  */
392 static void
393 xprt_rdma_set_port(struct rpc_xprt *xprt, u16 port)
394 {
395 	struct sockaddr *sap = (struct sockaddr *)&xprt->addr;
396 	char buf[8];
397 
398 	rpc_set_port(sap, port);
399 
400 	kfree(xprt->address_strings[RPC_DISPLAY_PORT]);
401 	snprintf(buf, sizeof(buf), "%u", port);
402 	xprt->address_strings[RPC_DISPLAY_PORT] = kstrdup(buf, GFP_KERNEL);
403 
404 	kfree(xprt->address_strings[RPC_DISPLAY_HEX_PORT]);
405 	snprintf(buf, sizeof(buf), "%4hx", port);
406 	xprt->address_strings[RPC_DISPLAY_HEX_PORT] = kstrdup(buf, GFP_KERNEL);
407 }
408 
409 /**
410  * xprt_rdma_timer - invoked when an RPC times out
411  * @xprt: controlling RPC transport
412  * @task: RPC task that timed out
413  *
414  * Invoked when the transport is still connected, but an RPC
415  * retransmit timeout occurs.
416  *
417  * Since RDMA connections don't have a keep-alive, forcibly
418  * disconnect and retry to connect. This drives full
419  * detection of the network path, and retransmissions of
420  * all pending RPCs.
421  */
422 static void
423 xprt_rdma_timer(struct rpc_xprt *xprt, struct rpc_task *task)
424 {
425 	xprt_force_disconnect(xprt);
426 }
427 
428 /**
429  * xprt_rdma_set_connect_timeout - set timeouts for establishing a connection
430  * @xprt: controlling transport instance
431  * @connect_timeout: reconnect timeout after client disconnects
432  * @reconnect_timeout: reconnect timeout after server disconnects
433  *
434  */
435 static void xprt_rdma_set_connect_timeout(struct rpc_xprt *xprt,
436 					  unsigned long connect_timeout,
437 					  unsigned long reconnect_timeout)
438 {
439 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
440 
441 	trace_xprtrdma_op_set_cto(r_xprt, connect_timeout, reconnect_timeout);
442 
443 	spin_lock(&xprt->transport_lock);
444 
445 	if (connect_timeout < xprt->connect_timeout) {
446 		struct rpc_timeout to;
447 		unsigned long initval;
448 
449 		to = *xprt->timeout;
450 		initval = connect_timeout;
451 		if (initval < RPCRDMA_INIT_REEST_TO << 1)
452 			initval = RPCRDMA_INIT_REEST_TO << 1;
453 		to.to_initval = initval;
454 		to.to_maxval = initval;
455 		r_xprt->rx_timeout = to;
456 		xprt->timeout = &r_xprt->rx_timeout;
457 		xprt->connect_timeout = connect_timeout;
458 	}
459 
460 	if (reconnect_timeout < xprt->max_reconnect_timeout)
461 		xprt->max_reconnect_timeout = reconnect_timeout;
462 
463 	spin_unlock(&xprt->transport_lock);
464 }
465 
466 /**
467  * xprt_rdma_connect - schedule an attempt to reconnect
468  * @xprt: transport state
469  * @task: RPC scheduler context (unused)
470  *
471  */
472 static void
473 xprt_rdma_connect(struct rpc_xprt *xprt, struct rpc_task *task)
474 {
475 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
476 	struct rpcrdma_ep *ep = r_xprt->rx_ep;
477 	unsigned long delay;
478 
479 	WARN_ON_ONCE(!xprt_lock_connect(xprt, task, r_xprt));
480 
481 	delay = 0;
482 	if (ep && ep->re_connect_status != 0) {
483 		delay = xprt_reconnect_delay(xprt);
484 		xprt_reconnect_backoff(xprt, RPCRDMA_INIT_REEST_TO);
485 	}
486 	trace_xprtrdma_op_connect(r_xprt, delay);
487 	queue_delayed_work(system_long_wq, &r_xprt->rx_connect_worker, delay);
488 }
489 
490 /**
491  * xprt_rdma_alloc_slot - allocate an rpc_rqst
492  * @xprt: controlling RPC transport
493  * @task: RPC task requesting a fresh rpc_rqst
494  *
495  * tk_status values:
496  *	%0 if task->tk_rqstp points to a fresh rpc_rqst
497  *	%-EAGAIN if no rpc_rqst is available; queued on backlog
498  */
499 static void
500 xprt_rdma_alloc_slot(struct rpc_xprt *xprt, struct rpc_task *task)
501 {
502 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
503 	struct rpcrdma_req *req;
504 
505 	req = rpcrdma_buffer_get(&r_xprt->rx_buf);
506 	if (!req)
507 		goto out_sleep;
508 	task->tk_rqstp = &req->rl_slot;
509 	task->tk_status = 0;
510 	return;
511 
512 out_sleep:
513 	task->tk_status = -ENOMEM;
514 	xprt_add_backlog(xprt, task);
515 }
516 
517 /**
518  * xprt_rdma_free_slot - release an rpc_rqst
519  * @xprt: controlling RPC transport
520  * @rqst: rpc_rqst to release
521  *
522  */
523 static void
524 xprt_rdma_free_slot(struct rpc_xprt *xprt, struct rpc_rqst *rqst)
525 {
526 	struct rpcrdma_xprt *r_xprt =
527 		container_of(xprt, struct rpcrdma_xprt, rx_xprt);
528 
529 	rpcrdma_reply_put(&r_xprt->rx_buf, rpcr_to_rdmar(rqst));
530 	if (!xprt_wake_up_backlog(xprt, rqst)) {
531 		memset(rqst, 0, sizeof(*rqst));
532 		rpcrdma_buffer_put(&r_xprt->rx_buf, rpcr_to_rdmar(rqst));
533 	}
534 }
535 
536 static bool rpcrdma_check_regbuf(struct rpcrdma_xprt *r_xprt,
537 				 struct rpcrdma_regbuf *rb, size_t size,
538 				 gfp_t flags)
539 {
540 	if (unlikely(rdmab_length(rb) < size)) {
541 		if (!rpcrdma_regbuf_realloc(rb, size, flags))
542 			return false;
543 		r_xprt->rx_stats.hardway_register_count += size;
544 	}
545 	return true;
546 }
547 
548 /**
549  * xprt_rdma_allocate - allocate transport resources for an RPC
550  * @task: RPC task
551  *
552  * Return values:
553  *        0:	Success; rq_buffer points to RPC buffer to use
554  *   ENOMEM:	Out of memory, call again later
555  *      EIO:	A permanent error occurred, do not retry
556  */
557 static int
558 xprt_rdma_allocate(struct rpc_task *task)
559 {
560 	struct rpc_rqst *rqst = task->tk_rqstp;
561 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(rqst->rq_xprt);
562 	struct rpcrdma_req *req = rpcr_to_rdmar(rqst);
563 	gfp_t flags = rpc_task_gfp_mask();
564 
565 	if (!rpcrdma_check_regbuf(r_xprt, req->rl_sendbuf, rqst->rq_callsize,
566 				  flags))
567 		goto out_fail;
568 	if (!rpcrdma_check_regbuf(r_xprt, req->rl_recvbuf, rqst->rq_rcvsize,
569 				  flags))
570 		goto out_fail;
571 
572 	rqst->rq_buffer = rdmab_data(req->rl_sendbuf);
573 	rqst->rq_rbuffer = rdmab_data(req->rl_recvbuf);
574 	return 0;
575 
576 out_fail:
577 	return -ENOMEM;
578 }
579 
580 /**
581  * xprt_rdma_free - release resources allocated by xprt_rdma_allocate
582  * @task: RPC task
583  *
584  * Caller guarantees rqst->rq_buffer is non-NULL.
585  */
586 static void
587 xprt_rdma_free(struct rpc_task *task)
588 {
589 	struct rpc_rqst *rqst = task->tk_rqstp;
590 	struct rpcrdma_req *req = rpcr_to_rdmar(rqst);
591 
592 	if (unlikely(!list_empty(&req->rl_registered))) {
593 		trace_xprtrdma_mrs_zap(task);
594 		frwr_unmap_sync(rpcx_to_rdmax(rqst->rq_xprt), req);
595 	}
596 
597 	/* XXX: If the RPC is completing because of a signal and
598 	 * not because a reply was received, we ought to ensure
599 	 * that the Send completion has fired, so that memory
600 	 * involved with the Send is not still visible to the NIC.
601 	 */
602 }
603 
604 /**
605  * xprt_rdma_send_request - marshal and send an RPC request
606  * @rqst: RPC message in rq_snd_buf
607  *
608  * Caller holds the transport's write lock.
609  *
610  * Returns:
611  *	%0 if the RPC message has been sent
612  *	%-ENOTCONN if the caller should reconnect and call again
613  *	%-EAGAIN if the caller should call again
614  *	%-ENOBUFS if the caller should call again after a delay
615  *	%-EMSGSIZE if encoding ran out of buffer space. The request
616  *		was not sent. Do not try to send this message again.
617  *	%-EIO if an I/O error occurred. The request was not sent.
618  *		Do not try to send this message again.
619  */
620 static int
621 xprt_rdma_send_request(struct rpc_rqst *rqst)
622 {
623 	struct rpc_xprt *xprt = rqst->rq_xprt;
624 	struct rpcrdma_req *req = rpcr_to_rdmar(rqst);
625 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
626 	int rc = 0;
627 
628 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
629 	if (unlikely(!rqst->rq_buffer))
630 		return xprt_rdma_bc_send_reply(rqst);
631 #endif	/* CONFIG_SUNRPC_BACKCHANNEL */
632 
633 	if (!xprt_connected(xprt))
634 		return -ENOTCONN;
635 
636 	if (!xprt_request_get_cong(xprt, rqst))
637 		return -EBADSLT;
638 
639 	rc = rpcrdma_marshal_req(r_xprt, rqst);
640 	if (rc < 0)
641 		goto failed_marshal;
642 
643 	/* Must suppress retransmit to maintain credits */
644 	if (rqst->rq_connect_cookie == xprt->connect_cookie)
645 		goto drop_connection;
646 	rqst->rq_xtime = ktime_get();
647 
648 	if (frwr_send(r_xprt, req))
649 		goto drop_connection;
650 
651 	rqst->rq_xmit_bytes_sent += rqst->rq_snd_buf.len;
652 
653 	/* An RPC with no reply will throw off credit accounting,
654 	 * so drop the connection to reset the credit grant.
655 	 */
656 	if (!rpc_reply_expected(rqst->rq_task))
657 		goto drop_connection;
658 	return 0;
659 
660 failed_marshal:
661 	if (rc != -ENOTCONN)
662 		return rc;
663 drop_connection:
664 	xprt_rdma_close(xprt);
665 	return -ENOTCONN;
666 }
667 
668 void xprt_rdma_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
669 {
670 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
671 	long idle_time = 0;
672 
673 	if (xprt_connected(xprt))
674 		idle_time = (long)(jiffies - xprt->last_used) / HZ;
675 
676 	seq_puts(seq, "\txprt:\trdma ");
677 	seq_printf(seq, "%u %lu %lu %lu %ld %lu %lu %lu %llu %llu ",
678 		   0,	/* need a local port? */
679 		   xprt->stat.bind_count,
680 		   xprt->stat.connect_count,
681 		   xprt->stat.connect_time / HZ,
682 		   idle_time,
683 		   xprt->stat.sends,
684 		   xprt->stat.recvs,
685 		   xprt->stat.bad_xids,
686 		   xprt->stat.req_u,
687 		   xprt->stat.bklog_u);
688 	seq_printf(seq, "%lu %lu %lu %llu %llu %llu %llu %lu %lu %lu %lu ",
689 		   r_xprt->rx_stats.read_chunk_count,
690 		   r_xprt->rx_stats.write_chunk_count,
691 		   r_xprt->rx_stats.reply_chunk_count,
692 		   r_xprt->rx_stats.total_rdma_request,
693 		   r_xprt->rx_stats.total_rdma_reply,
694 		   r_xprt->rx_stats.pullup_copy_count,
695 		   r_xprt->rx_stats.fixup_copy_count,
696 		   r_xprt->rx_stats.hardway_register_count,
697 		   r_xprt->rx_stats.failed_marshal_count,
698 		   r_xprt->rx_stats.bad_reply_count,
699 		   r_xprt->rx_stats.nomsg_call_count);
700 	seq_printf(seq, "%lu %lu %lu %lu %lu %lu\n",
701 		   r_xprt->rx_stats.mrs_recycled,
702 		   r_xprt->rx_stats.mrs_orphaned,
703 		   r_xprt->rx_stats.mrs_allocated,
704 		   r_xprt->rx_stats.local_inv_needed,
705 		   r_xprt->rx_stats.empty_sendctx_q,
706 		   r_xprt->rx_stats.reply_waits_for_send);
707 }
708 
709 static int
710 xprt_rdma_enable_swap(struct rpc_xprt *xprt)
711 {
712 	return 0;
713 }
714 
715 static void
716 xprt_rdma_disable_swap(struct rpc_xprt *xprt)
717 {
718 }
719 
720 /*
721  * Plumbing for rpc transport switch and kernel module
722  */
723 
724 static const struct rpc_xprt_ops xprt_rdma_procs = {
725 	.reserve_xprt		= xprt_reserve_xprt_cong,
726 	.release_xprt		= xprt_release_xprt_cong, /* sunrpc/xprt.c */
727 	.alloc_slot		= xprt_rdma_alloc_slot,
728 	.free_slot		= xprt_rdma_free_slot,
729 	.release_request	= xprt_release_rqst_cong,       /* ditto */
730 	.wait_for_reply_request	= xprt_wait_for_reply_request_def, /* ditto */
731 	.timer			= xprt_rdma_timer,
732 	.rpcbind		= rpcb_getport_async,	/* sunrpc/rpcb_clnt.c */
733 	.set_port		= xprt_rdma_set_port,
734 	.connect		= xprt_rdma_connect,
735 	.buf_alloc		= xprt_rdma_allocate,
736 	.buf_free		= xprt_rdma_free,
737 	.send_request		= xprt_rdma_send_request,
738 	.close			= xprt_rdma_close,
739 	.destroy		= xprt_rdma_destroy,
740 	.set_connect_timeout	= xprt_rdma_set_connect_timeout,
741 	.print_stats		= xprt_rdma_print_stats,
742 	.enable_swap		= xprt_rdma_enable_swap,
743 	.disable_swap		= xprt_rdma_disable_swap,
744 	.inject_disconnect	= xprt_rdma_inject_disconnect,
745 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
746 	.bc_setup		= xprt_rdma_bc_setup,
747 	.bc_maxpayload		= xprt_rdma_bc_maxpayload,
748 	.bc_num_slots		= xprt_rdma_bc_max_slots,
749 	.bc_free_rqst		= xprt_rdma_bc_free_rqst,
750 	.bc_destroy		= xprt_rdma_bc_destroy,
751 #endif
752 };
753 
754 static struct xprt_class xprt_rdma = {
755 	.list			= LIST_HEAD_INIT(xprt_rdma.list),
756 	.name			= "rdma",
757 	.owner			= THIS_MODULE,
758 	.ident			= XPRT_TRANSPORT_RDMA,
759 	.setup			= xprt_setup_rdma,
760 	.netid			= { "rdma", "rdma6", "" },
761 };
762 
763 void xprt_rdma_cleanup(void)
764 {
765 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
766 	if (sunrpc_table_header) {
767 		unregister_sysctl_table(sunrpc_table_header);
768 		sunrpc_table_header = NULL;
769 	}
770 #endif
771 
772 	xprt_unregister_transport(&xprt_rdma);
773 	xprt_unregister_transport(&xprt_rdma_bc);
774 }
775 
776 int xprt_rdma_init(void)
777 {
778 	int rc;
779 
780 	rc = xprt_register_transport(&xprt_rdma);
781 	if (rc)
782 		return rc;
783 
784 	rc = xprt_register_transport(&xprt_rdma_bc);
785 	if (rc) {
786 		xprt_unregister_transport(&xprt_rdma);
787 		return rc;
788 	}
789 
790 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
791 	if (!sunrpc_table_header)
792 		sunrpc_table_header = register_sysctl("sunrpc", xr_tunables_table);
793 #endif
794 	return 0;
795 }
796